Studies will include continuation of factors related to protein-protein interactions in several different systems. These include interaction between malate dehydrogenase (both cytoplasmic and mitochondrial) with aspartic amino transferase (cytoplasmic and mitochondrial); between liver glutamate dehydrogenase and liver aspartic amino transferase; and between muscle adenylate deaminase and myosin. Other studies include a comparison of the glutamate dehydrogenase catalyzed and the uncatalyzed disulfonation of trinitrobenzene sulfonate and its analogs by NADH. Techniques to be used include stopped flow activity measurements and computer analysis of full time course kinetic data as well as conventional methods. Structure activity relationships concerning phosphofructokinase are to be studied with particular reference to the pH dependent cold lability of the enzyme. In this regard we are extending simple allosteric enzyme. In this regard we are extending simple allosteric enzyme models to include two substrate cases. BIBLIOGRAPHIC REFERENCE: Kurz, L. C. and Frieden, C. (1975) J. Am. Chem. Soc. 97, 677-679. A Model Dehyrogenase Reaction. Charge Distribution in the Transition State. Kurz, L. C. and Frieden, C. (1975) Fed. Proc. 34, 523. A Model Reaction for the Chemical Mechanism of Glutamate Dehydrogenase.